B-class patrol boat

B-class Motor Launches

The B-class motor launches would have added considerably to the anti-submarine capacity of the Royal Netherlands Navy. They were similar in size and purpose to the British motor launches, which were produced in large numbers during the war. None were completed before the fall of the Netherlands East Indies. The Japanese navy raised and completed a number of them. The exact identities of these ships are not known.

B-class motor launches in Japanese service

Construction details

Name B 1 - B 8 B 9 - B 12 B 13 - B 16

Dockyard Marine Etablissement, Soerabaja Droogdok Mij. Soerabaja, Soerabaja Droogdok Mij. Tandjong Priok, Batavia

Specifications

Design Imperial Japanese Navy

Displacement 130 tons

Crew ca. 18

Dimensions 45,6 (oa) 42,4 (pp) x 5,0 x 1,4 m.

Armament 1 x 75 mm
1 x 37 mm
2 x 12.7 mm machine guns 1 x 50 mm
1 x 25 mm
1 x 13 mm machine gun

ASW 20 depthcharges 32 deptcharges

Propulsion details
	Design	Imperial Japanese Navy
Machinery	2 diesel engines	petrol engines (see Performance)
Shafts	2	2
Performance	1900 hp	Cha 103/114/115: 1500 hp (2 petrol engines ) Cha 106 : 1200 hp (3 Lorraine petrol engines )* Cha 105: 1800 hp (4 Carmouth petrol engines) Cha 107/108: 1800 hp (4 Lorraine petrol engines)*
Max Speed	19 knots	Cha 114/115: 19 knots Cha 106 : 16,5 knots Others: 20 knots
* Like the TM-4 class MTBs, these engines were most likely taken from old Fokker T 4 and Dornier Wal floatplanes. They were usually worn out and needed a lot of maintenance.

Histories

Cha 103 Launched in 1942. Former B 1, commissioned on August 31, 1942 as Cha 103. Captured August, 1945 at Ambon by Australian navy. Official transfer to the Netherlands Navy September 22, 1945. Subsequent fate unknown.

Cha 105 Captured at dockyard and launched on January 11, 1943. Completed January 26, 1944. Sunk by submarine HMS Taciturn on June 16, 1945 off Soerabaja.

Cha 106 Captured at dockyard and launched March 24, 1943. Completed September 2, 1944 as Cha 106. Captured at Batavia August, 1945 and returned to the Netherlands Navy. Subsequent fate unknown.

Cha 107 Launched February 27, 1943 as Cha 107 and completed on January 30, 1945. Captured in Batavia in August, 1945, laid up until 1947. Then used as accommodation vessel. Subsequent fate unknown.

Cha 108 Launched April 22, 1943 at dockyard, but not yet completed when carrier-based aircraft from USS Saratoga and HMS Illustrious attacked Soerabaja on May 17, 1944. Sunk, but raised. She was still under repair when captured in 1945.

Cha 114 Launched November 30, 1943 and commissioned June 23, 1944 as Cha 114. Heavily damaged by HMS Stygian or USS Hawkbill on April 15, 1945 in position. In damaged condition when captured at Soerabaja in August, 1945.

Cha 115 Launched late June, 1943 and commissioned September 2, 1944. Captured at Soerabaja in August 1945 and later used as a ferry between Soerabaja and Madura. Subsequent fate unknown.

Sources and related links

Sources
A.J. Vermeulen "De schepen van de Koninklijke Marine en die der gouvernementsmarine 1814-1962 (1962)
F.C. Backer Dirks "De Gouvernements Marine in het voormalige Nederlands-Indie 1861-1949, volume 3 (1986)
Chr. Mark "Schepen van de Koninklijke Marine in W.O. II" (1997)
L.L. von Münching "Schepen van de Kon. Marine in de 2e Wereldoorlog" (1978)
Ph.M. Bosscher "De Koninklijke Marine in de Tweede Wereldoorlog", volume 2 (1986)

Related links (please report any broken links)
The official chronology of the US Navy in World War II - 1945 (off- site link)

May 31, 2006 Revised data

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Construction details
Name	B 1 - B 8	B 9 - B 12	B 13 - B 16
Dockyard	Marine Etablissement, Soerabaja	Droogdok Mij. Soerabaja, Soerabaja	Droogdok Mij. Tandjong Priok, Batavia

Specifications
	Design	Imperial Japanese Navy
Displacement	130 tons
Crew		ca. 18
Dimensions	45,6 (oa) 42,4 (pp) x 5,0 x 1,4 m.
Armament	1 x 75 mm 1 x 37 mm 2 x 12.7 mm machine guns	1 x 50 mm 1 x 25 mm 1 x 13 mm machine gun
ASW	20 depthcharges	32 deptcharges

Histories
Cha 103	Launched in 1942. Former B 1, commissioned on August 31, 1942 as Cha 103. Captured August, 1945 at Ambon by Australian navy. Official transfer to the Netherlands Navy September 22, 1945. Subsequent fate unknown.
Cha 105	Captured at dockyard and launched on January 11, 1943. Completed January 26, 1944. Sunk by submarine HMS Taciturn on June 16, 1945 off Soerabaja.
Cha 106	Captured at dockyard and launched March 24, 1943. Completed September 2, 1944 as Cha 106. Captured at Batavia August, 1945 and returned to the Netherlands Navy. Subsequent fate unknown.
Cha 107	Launched February 27, 1943 as Cha 107 and completed on January 30, 1945. Captured in Batavia in August, 1945, laid up until 1947. Then used as accommodation vessel. Subsequent fate unknown.
Cha 108	Launched April 22, 1943 at dockyard, but not yet completed when carrier-based aircraft from USS Saratoga and HMS Illustrious attacked Soerabaja on May 17, 1944. Sunk, but raised. She was still under repair when captured in 1945.
Cha 114	Launched November 30, 1943 and commissioned June 23, 1944 as Cha 114. Heavily damaged by HMS Stygian or USS Hawkbill on April 15, 1945 in position. In damaged condition when captured at Soerabaja in August, 1945.
Cha 115	Launched late June, 1943 and commissioned September 2, 1944. Captured at Soerabaja in August 1945 and later used as a ferry between Soerabaja and Madura. Subsequent fate unknown.